Intravenous drug users (IVDUs) occupy a pivotal position in the AIDS epidemic because of their association with others who would not be at risk if it were not for their association with an IVDU. Second only to intravenous drug use, heterosexual contact with males at risk is the largest transmission category among women testing positive for the virus. Recently, the emergence of crack cocaine has prompted new fears, due both to its highly addictive nature and its association with sexual promiscuity. For the past two and a half years we have been a subcontractor in NIDA's Indigenous Leader Outreach efforts aimed at reducing HIV risks among intravenous drug users. We have interviewed over 500 IVDUs in this effort and have performed extensive analysis of these data. We are now proposing a controlled test of the enhanced features of that project. We are also proposing to expand the target population to include crack cocaine users and sexual partners. Specifically, a standard intervention approach, consisting of distribution of prevention packets and educational materials, will be compared to an Intensive Extended-network intervention, including the same components as the standard model plus the use of indigenous outreach staff who serve as public health advocates. Outreach workers engage high risk individuals in assessing risk, exploring alternative strategies, and reinforcing these efforts through repeated contacts over time. Both models will include HIV testing with pre and post-test counseling, structured pre and post-test interviews and ethnography. We hypothesize that the enhanced intervention will produce greater risk reduction, more knowledge gain, and an increased number of corollary benefits (e.g. employment, treatment admissions) than will the standard approach. An experimental design will be utilized to test these hypotheses: each of two targeted sites with high volume intravenous and crack use will be randomly assigned either the enhanced or standard intervention for a 24-month period; following a three-month "washout" period, a crossover will occur and the second intervention implemented for the same length of time in the same neighborhoods. Only one model will be active in a site at any point; however, over the course of the study both targeted neighborhoods will be exposed to both interventions. The study will be evaluation using both formative and summative methodologies. Analyses will employ repeated measures multivariate statistical techniques appropriate for crossover designs.